I think it is great that you are giving your audience a chance to express their preferences on important issues.
First of all, from my experiences over the last decade, commercial e-commerce packages have been overpriced, oversold and underperforming, and even if they are competent they lock you into a situation shere you have no control and are really a prisoner to their wishes. Even though it is a desktop, Microsoft Vista tells it all. And lots of these commercial entities are no longer around.
For our firm, control is crucial, and we get that with a variety of open source packages, where we have all the source code and the backing of one of the largest open source entities - Apache Foundation. We have gone the SAAS route, and installed a Java based, Apache Foundation honed CRM for our use and those of our small biz customers.
We are our own merchant, and we are also the "tech support" for small businesses who can't afford even a parttime programmer. But things must be different in the San Francisco bay area, because we have no problem finding computer science grads or advanced students from Berkeley who will provide us with needed services for $15 per hour. Given that we have control, we can choose when to upgrade, and because we are using a unitary system, rather than a mishmash of add-ins, we don't have upgrade problems. We also chose a BSD licensed software package, because when we spend our money improving and extending the software, we don't have to share our improvements with our competition, like you have to do with a GPL based system like Joomla and Drupal and Hipergate, etc.
We chose Java based, because that is becoming the el primo language of the business world, as opposed to PHP/mysql packages, which are slower, less scalable, and as one reader already mentioned, fraught with more headaches. We also chose postgresql as our database, because current benchmarks demonstrate it is now superior to mysql in terms of simultaneous users, and it is independent, unlike mysql which was purchased by Sun, who are taking it in a less friendly direction and where all of the original developers are now leaving in droves.
Our systems also allow integration with VOIP, and other pieces such as collaboration as well. Once you go to open source, and learn to take advantage of the dynamic open source communities that surrounds an application, you nevet go back to commercial. And you definitely see it in your bottom line.